[Wien] d-eg orbitals are not effected by applying Ueff
pieper
pieper at ifp.tuwien.ac.at
Sat Jan 28 20:51:18 CET 2017
From the abstract of the paper you cited in your last mail I gather that
this an alloy. So I suspect that there is some cite disorder with Co as
well as Ga occupying the lattice sites randomly?
In that case Co would have a number of different configurations, due to
the random distribution, that are not represented in your .struct file.
As for the gap: This was a question, not stating some fact.
Unfortunately I did not follow the literature on GGA+U, so I am not
aware of any studies with the same problem as yours. But I am also not
aware of any study saying that a (reasonably sized) U MUST produce a
gap. Here the real experts might provide more useful comments.
Best regards,
Martin Pieper
---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564
Am 28.01.2017 01:21, schrieb venkatesh chandragiri:
> Dear Prof. Pieper,
>
> the answers are as follows,
>
> I UNDERSTAND THAT THIS IS AN ALLOY? IF YES, WHAT KIND OF SUPERCELL DO
> YOU USE TO MODEL THE SYSTEM?
>
> I do not used any supercell configuration. The case.struct file
> contains the two atoms as given below.
>
> ARE THESE T2G AND EG SYMMETRIES ACTUALLY PRESENT IN ALL POSSIBLE
> CONFIGURATIONS WITHIN THE ALLOY (PROBABLY NOT)? IS IT POSSIBLE THAT
> THE SYMMETRY YOU ARTIFICIALLY IMPOSE IS AT THE BOTTOM OF THIS?
>
> Experimentally, at room temperature, we have refined the crystal
> structure of the Co50Ga50 alloy and the same used for the generating
> the case.struct. I do not understand the your meaning of " all
> possible configurations ".
>
> WHY DO YOU BELIEVE THAT U SHOULD ACT IN THE SAME WAY ON DIFFERENT
> SYMMETRIES? COULD IT BE THAT LOCALIZING T2G PAYS OFF MUCH BETTER THAN
> EG?
>
> I do not have experience before on the DFT +U studies, but have seen
> in literature that one could create artifical energy gap by applying U
> in order to explain the insulating behaviour of few oxides. It would
> be helpful for me, if you provide me some references where the
> localizing t2g pays off much better than eg by applying U.
>
> DID YOU TRY OTHER CONFIGURATIONS / SUPERCELLS / SYMMETRIES?
>
> I tried DFT + SO + U , but this also leads to the same feature in DOS
> like DFT + U case. No supercells are tried. Could you please suggest
> me next step or possible configurations so that I can give a try.
>
> thanks for your reply and looking forward to your help
>
> venkatesh
>
> =========== Co50Ga50.struct ===========
>
> Co50Ga50
>
> P LATTICE,NONEQUIV.ATOMS: 2 221_Pm-3m
>
> MODE OF CALC=RELA unit=bohr
>
> 5.438632 5.438632 5.438632 90.000000 90.000000 90.000000
>
> ATOM 1: X=0.00000000 Y=0.00000000 Z=0.00000000
> MULT= 1 ISPLIT= 2
> Ga1 NPT= 781 R0=0.00005000 RMT= 2.2400 Z: 31.0
>
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> ATOM 2: X=0.50000000 Y=0.50000000 Z=0.50000000
> MULT= 1 ISPLIT= 2
> Co1 NPT= 781 R0=0.00005000 RMT= 2.3500 Z: 27.0
>
> LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
> 0.0000000 1.0000000 0.0000000
> 0.0000000 0.0000000 1.0000000
> 48 NUMBER OF SYMMETRY OPERATIONS
> -1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0-1 0.00000000
> 1
> -1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0 1 0.00000000
> 2
> -1 0 0 0.00000000
> 0 0-1 0.00000000
> 0-1 0 0.00000000
> 3
> -1 0 0 0.00000000
> 0 0 1 0.00000000
> 0-1 0 0.00000000
> 4
> -1 0 0 0.00000000
> 0 0-1 0.00000000
> 0 1 0 0.00000000
> 5
> -1 0 0 0.00000000
> 0 0 1 0.00000000
> 0 1 0 0.00000000
> 6
> -1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0-1 0.00000000
> 7
> -1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0 1 0.00000000
> 8
> 0-1 0 0.00000000
> -1 0 0 0.00000000
> 0 0-1 0.00000000
> 9
> 0-1 0 0.00000000
> -1 0 0 0.00000000
> 0 0 1 0.00000000
> 10
> 0 0-1 0.00000000
> -1 0 0 0.00000000
> 0-1 0 0.00000000
> 11
> 0 0 1 0.00000000
> -1 0 0 0.00000000
> 0-1 0 0.00000000
> 12
> 0 0-1 0.00000000
> -1 0 0 0.00000000
> 0 1 0 0.00000000
> 13
> 0 0 1 0.00000000
> -1 0 0 0.00000000
> 0 1 0 0.00000000
> 14
> 0 1 0 0.00000000
> -1 0 0 0.00000000
> 0 0-1 0.00000000
> 15
> 0 1 0 0.00000000
> -1 0 0 0.00000000
> 0 0 1 0.00000000
> 16
> 0-1 0 0.00000000
> 0 0-1 0.00000000
> -1 0 0 0.00000000
> 17
> 0-1 0 0.00000000
> 0 0 1 0.00000000
> -1 0 0 0.00000000
> 18
> 0 0-1 0.00000000
> 0-1 0 0.00000000
> -1 0 0 0.00000000
> 19
> 0 0 1 0.00000000
> 0-1 0 0.00000000
> -1 0 0 0.00000000
> 20
> 0 0-1 0.00000000
> 0 1 0 0.00000000
> -1 0 0 0.00000000
> 21
> 0 0 1 0.00000000
> 0 1 0 0.00000000
> -1 0 0 0.00000000
> 22
> 0 1 0 0.00000000
> 0 0-1 0.00000000
> -1 0 0 0.00000000
> 23
> 0 1 0 0.00000000
> 0 0 1 0.00000000
> -1 0 0 0.00000000
> 24
> 0-1 0 0.00000000
> 0 0-1 0.00000000
> 1 0 0 0.00000000
> 25
> 0-1 0 0.00000000
> 0 0 1 0.00000000
> 1 0 0 0.00000000
> 26
> 0 0-1 0.00000000
> 0-1 0 0.00000000
> 1 0 0 0.00000000
> 27
> 0 0 1 0.00000000
> 0-1 0 0.00000000
> 1 0 0 0.00000000
> 28
> 0 0-1 0.00000000
> 0 1 0 0.00000000
> 1 0 0 0.00000000
> 29
> 0 0 1 0.00000000
> 0 1 0 0.00000000
> 1 0 0 0.00000000
> 30
> 0 1 0 0.00000000
> 0 0-1 0.00000000
> 1 0 0 0.00000000
> 31
> 0 1 0 0.00000000
> 0 0 1 0.00000000
> 1 0 0 0.00000000
> 32
> 0-1 0 0.00000000
> 1 0 0 0.00000000
> 0 0-1 0.00000000
> 33
> 0-1 0 0.00000000
> 1 0 0 0.00000000
> 0 0 1 0.00000000
> 34
> 0 0-1 0.00000000
> 1 0 0 0.00000000
> 0-1 0 0.00000000
> 35
> 0 0 1 0.00000000
> 1 0 0 0.00000000
> 0-1 0 0.00000000
> 36
> 0 0-1 0.00000000
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 37
> 0 0 1 0.00000000
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 38
> 0 1 0 0.00000000
> 1 0 0 0.00000000
> 0 0-1 0.00000000
> 39
> 0 1 0 0.00000000
> 1 0 0 0.00000000
> 0 0 1 0.00000000
> 40
> 1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0-1 0.00000000
> 41
> 1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0 1 0.00000000
> 42
> 1 0 0 0.00000000
> 0 0-1 0.00000000
> 0-1 0 0.00000000
> 43
> 1 0 0 0.00000000
> 0 0 1 0.00000000
> 0-1 0 0.00000000
> 44
> 1 0 0 0.00000000
> 0 0-1 0.00000000
> 0 1 0 0.00000000
> 45
> 1 0 0 0.00000000
> 0 0 1 0.00000000
> 0 1 0 0.00000000
> 46
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0-1 0.00000000
> 47
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0 1 0.00000000
> 48
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